Sunday, April 29, 2007

The application of a redispersible latex blend for the analysis of the physiology of hydrogen producing Rhodopseudomonas palustris in 6.25 and 100 cm2 coatings

Jimmy L. Gosse1, Brian J. Engel1, Jeremy C. Hui2, Federico E. Rey3, Caroline S. Harwood3, and Michael C. Flickinger4. (1) Department of Biochemistry, Molecular Biology & Biophysics, BioTechnology Institute, University of Minnesota, 1479 Gortner Ave., St. Paul, MN 55108, (2) Department of Chemical Engineering and Materials Science, BioTechnology Institute, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN 55455, (3) Department of Microbiology, University of Washington, Box 357242, Seattle, WA 98195, (4) Microbiology; Chemcial and Biomolecular Engineering; BTEC, North Carolina State University, Centennial Campus, Campus Box 7928, Raleigh, NC 27695

The hydrogen production rate from <70 μm thick latex coatings containing non-growing Rhodopseudomonas palustris CGA009 in the presence of 20 mM acetate is stable for >2000 hours at 2 mmol H2 m-2 hr-1.  We have recently scaled the micro-photobioreactor to a 1:100th m2 (10x10 cm coating). Although the stable hydrogen production rate is significant it is lower than the initial rate of 6.3 mmol H2 m-2 hr-1 observed in the first 80 hours of hydrogen production.  A number of phenomenon could be responsible for the drop in production rate including: loss of viability, protein inactivation/degradation of key intracellular components, and altered coating porosity.  Accurate and reproducible determination of the non-growth physiology during hydrogen produciton is not possible with out coating dispersion.  Described here is a redispersible latex blend that is stable enough for hydrogen production however is dispersible with mild sonication and vortexing allowing for viability and western blot analysis.